Since 1890, Hadfield had developed the Fe-Mn-Al-C based alloy system which had been designed and patented by many people, for example, U.S. Pat. Nos. 422,403, 1,892,316, 3,111,405, 3,210,230, and Canada patent No. 655,824 and etc. In those years, this alloy system had always failed to be commercialized and industrialized. According to all of the former patents, no detailed and practical manufacture and fabrication processes of this alloy system had been invented before. Most important of all, no good corrosion resistant Fe-Mn-Al-C based alloy which is comparable to stainless 304, 430 had been developed in those past patents.
By the way, the melting process of the mass production of the Fe-Mn-Al-C based alloys is also a problem which was never solved before. Only the induction furnace melting process was used in these past patents and the production quantity was restricted by the small capacity of the induction furnace. It is also known that aluminum can not be melted in the arc furnace. Under such consideration, it is impossible to melt the Fe-Mn-Al-C based alloy in the arc furnace directly. A better way to melt the alloy is disclosed in this patent.
To obtain products with comparable good corrosion resistances such as S.S. 430,304 for the Fe-Mn-Al-C based alloys, it cannot depend on the chemical composition arrangements only. A series of detailed manufacture, fabrication processes and special surface treatments are included in this invention.